1. Field of the Invention
The present invention relates to network management, and more specifically to a method and apparatus for efficiently retrieving desired information from network elements.
2. Related Art
Agents are often implemented associated with network elements to provide information of interest about network elements. In a typical scenario, an agent receives a request for information (related to a network element) from a network management station (NMS), and sends a response containing the requested information. The agent may interface with the network element to gather the requested information before generating the response.
To facilitate communication between a NMS and agents, management protocols such as Simple Network Management Protocol (SNMP) have been used. The management protocols in turn identify specific information of interest using Management Information Bases (MIB). A MIB (hereafter “base MIB”) generally specifies information elements of interest for each entity (e.g., interface, system, etc.) and generally assigns a unique identifier associated with each information element. For example, a get-request command may contain a number 1.3.6.1.2.1.2.2.1 to identify that the value in a counter maintaining Ethernet Collisions is to be provided.
An NMS may use commands such as get-request or get-next request to request specific information related to a network element from an agent. A get-request command is used when there is only a single instance of the information. On the other hand a get-next request command is used to request one of many instances of information. A receiving agent retrieves the requested data/information from the MIB and sends a response with the retrieved information.
One problem with the above noted basic approach (SNMP version 1) is that retrieval of many instances of information (viewed as a table) generally requires a corresponding number of get-next request commands (and responses thereto). The processing and traffic overhead resulting from such requests/responses may be undesirable at least in some environments (particularly in large networks).
Accordingly, later implementations of SNMP (described in “RFC 1905: Protocol Operations for Version 2 of the Simple Network Management Protocol (SNMPv2)”, incorporated into the present application in its entirety herewith) generally provided for more commands such as Get-Bulk request which enables multiple instances of the information to be retrieved using a single request. Accordingly, processing and traffic overhead may be reduced in comparison to SNMP version 1 based implementation.
However, one limitation of SNMP version 2 is that a user may have to cause retrieval of all instances in a range even if only some of the dis-contiguous instances are of interest. For example, assuming that instances 5-10, 398, and 500-700 are of interest, all the instances 5-700 may need to be requested to retrieve the information using a single request. Again, the processing and traffic overhead resulting from retrieval of unneeded instances may be undesirable.
Another limitation of SNMP version 2 is that multiple requests may need to be sent to retrieve information in different base MIBs. The resulting processing and traffic overhead may also be undesirable.
Therefore, what is needed is a method and apparatus for retrieving desired information from agents while meeting one or more of such requirements.
In the drawings like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.